Autoclaving, dry heat and chemical vapor sterilization methods have been accepted as most effective means for sterilizing inanimate objects such as medical and dental instruments and equipment used in patient treatment. Such methods, however, do have certain disadvantages. The processes are too tedious and cumbersome, and they require long contact times to achieve sterilization. Further, the sterilization process requires highly skilled personnel to operate and monitor the system. Many pieces of equipment, surgical instruments and material used in patient treatment are heat sensitive and too delicate to be exposed to sterilization methods requiring high temperatures. Additionally, some objects which require sterilization are not located at sites where the sterilization equipment is located.
There has been a considerable amount of research directed to finding alternative methods for sterilizing other than those requiring high temperatures. Many of the research efforts have pointed to sterilizing in liquid phase. A search of the scientific literature and the prior art has produced many examples directed to improving the aqueous sporicidal composition of germicides used to disinfect animate and inanimate surfaces and objects.
Glutaraldehyde in aqueous solution has received considerable attention aimed at increasing its potency and rapidity of sporicidal activity by the use of various combinations of active ingredients; or by increasing the temperature of the aqueous solution of glutaraldehyde enhanced by ultrasonic energy. To date, however, aqueous solutions of glutaraldehyde require from 6 3/4 hours to 10 hours contact time to destroy highly resistant spores such as Bacillus subtilis and Clostridium sporogenes. For this reason, aqueous solutions of glutaraldehyde are still relegated to a disinfecting role.
Liquid germicides hold out great promise as liquid sterilants if their antimicrobial properties can be accelerated to considerably shorten contact time for sporicidal action. The need for germicides in liquid phase having rapid and potent disinfecting and sterilizing compositions is highly desirable for inactivating microorganisms on inanimate and animate surfaces and objects. Germicides employed to disinfect and sterilize inanimate objects are termed "disinfectants"; those germicides employed to disinfect and sterilize animate surfaces are termed "antiseptics." Germicides should be able to penetrate into crevices, cavities, and beneath films of organic matter. Moreover, germicides should possess and maintain a strong lethal concentration in the presence of sputum, blood and fecal material. Germicides should have a wide antimicrobial spectrum; and importantly, germicides should achieve and maintain a low surface tension to enable effective and rapid absorption of the active ingredients at interface with a contaminated object.
Surfactants are extremely important in aqueous solution to lower surface tension. Without a surfactant, the antimicrobial activity of an aqueous solution is severely compromised. The efficacy of this invention is directed to the use of surfactants having opposing electrical charges, and which are generally considered to be incompatible when used together in aqueous solutions. Based on observations when these surfactants (anionic and cationic surface active agents) are exposed together experimentally, in aqueous solutions, they exhibit dramatic and outstanding properties in lowering surface tension not observed before. This invention is able to maintain and prevent the premature exposure and interaction of these surfactants to each other within a device, until the disinfecting process is initiated. When employing anionic and cationic surfactants in a 2% aqueous solution of acid glutaraldehyde, highly resistant spores are destroyed within 5-10 minutes, versus 6 3/4-10 hours in the conventional immersion system.
This invention makes use of a liquid absorbent material which contains, as dry constituents, anionic and cationic surfactants milled into said absorbent material at the manufacturing stage. When exposed to an aqueous solution, the surfactants are released from the liquid absorbent material to enhance significantly the surface active properties of said aqueous solution.
Aqueous solutions having cleaning, disinfecting, or sterilizing compositions, have their surface active properties greatly enhanced where anionic and cationic surfactants are employed. Because of their superior surface active activities when used together in aqueous solution, the need for long contact time necessary for antimicrobial activity is eliminated. A germicide like glutaraldehyde is elevated from a disinfectant to a liquid sterilant. A germicide, supplemented with anionic and cationic surfactants employed as an antiseptic, is able to reduce quickly the microorganism population residing on animate surfaces such as skin, mucosal membrane, and wound sites. The application of the invention is not limited to cleaning, disinfecting, and sterilizing purposes in the health field, but can be used to enhance aqueous solutions used as mouth washes, toothpastes and similar products to remove foreign material and bacteria from animate surfaces and inanimate objects.
It is accordingly one object of the present invention to present a device and method for storing anionic and cationic surfactants in a nonreactive state prior to use. It is accordingly another object of the present invention to present a potent sporicidal composition which can rapidly destroy highly resistant spores within minutes when practiced within the scope of the invention. It is another object of the present invention to demonstrate the strong enhancement of surface active properties achieved when employing the above surfactants in aqueous solutions. It is the further object of this invention to achieve rapid sporicidal activity, resulting in total destruction of highly resistant spores within minutes (5-10 minutes). And finally, in addition to the health field, it is another object of the present invention to apply the invention in a wide variety of applications such as in aqueous media of industrial and household products.
Referring now to the novelty and innovativeness of the invention, a search of the scientific literature and the prior art reveal no instance where anionic and cationic surfactants are employed together to lower surface tension in aqueous solution. For example, U.S. Pat. No. 3,282,775 (Stonehill) discloses the use of a cationic surfactant, only. U.S. Pat. No. 3,912,450 (Boucher) describes the use of anionic and nonionic surfactants together in aqueous solutions. U.S. Pat. No. 4,093,744 (Winicov) describes the use individually or severally nonionic, anionic and amphoteric surfactants.